1. Field of the Invention
Priority is claimed on Japanese Patent Application No. 2004-163033, filed Jun. 1, 2004, the contents of which are incorporated herein by reference.
The present invention relates to a vehicle body frame structure and, in particular, to an improvement in the rigidity thereof.
2. Description of Related Art
Technology has been developed for a vehicle frame structure that achieves an improvement in rigidity as a result of joining a side sill to a rear frame such that they form a continuous member by joining a front end portion of the rear frame to an inner side of a rear end portion of the side sill (see, for example, Japanese Patent Application Examined Publication No. 62-60309. If a side sill and rear frame are joined together so as to be continuous in this manner, the space utilization efficiency is also improved. Consequently, this type of structure has the merit of allowing the space for installing a fuel tank and the like to be enlarged.
In a structure in which a side sill and rear frame are joined together continuously in this manner, a curved portion is provided in the vicinity of a boundary between the side sill that is positioned at a bottom portion of the vehicle body side portion and the rear frame that is positioned to the rear of the side sill so as to avoid the rear tire. The strength of this curved portion is slightly reduced.
Accordingly, it is an object of the present invention to provide a vehicle body frame structure that enables an improvement to be obtained in the strength of a curved portion in the vicinity of a boundary between a side sill and a rear frame when these are joined together continuously.